Many wireless systems provide enhanced security from outside hacking beyond the encryption provided by the 802.11 standard. This additional security often involves not emitting beacon signals from the access point. This provides a measure of security in that an intruder must be able to identify the wireless network in order to intrude. Unfortunately, by not transmitting the beacon signals from the access point other wireless networks may be unaware that the wireless system exists.
One problem with this technique is that the channel used by the secure system appears to be available to other wireless networks by virtue of absence of the beacon. Other networks usually check for a beacon signal before choosing a channel for operation and attempting to use it. The 802.11.h standard describes measuring channel occupancy to avoid channels that are in use by another network. This security technique, thus, provides enhanced security, but may inherently result in increased interference by virtue of another network being set up to use the same channel. This will be a growing problem as the number of wireless access points proliferates.